MIKC* MADS Domain Heterodimers Are Required for Pollen Maturation and Tube Growth in Arabidopsis
MIKC* MADS Domain Heterodimers Are Required for Pollen Maturation and Tube Growth in Arabidopsis
复制标题
DOI：
10.1104/pp.109.135806
复制
发表时间：
2009-04-01
期刊：
影响因子：
7.4
通讯作者：
Fernandez, Donna E.
中科院分区：
文献类型：
--
作者：
Adamczyk, Benjamin J.;Fernandez, Donna E.
MADS盒基因编码的转录因子在植物发育的各个阶段起着重要的调控作用。编码MIKC* 型（MADS DNA结合结构域、介导结构域、角蛋白样结构域和C-末端结构域）因子的转录物是一个分歧的进化枝，在成熟花粉中富集。以前的研究表明，这些蛋白质结合DNA作为异二聚体，形成之间的S-和P-类MIKC* 蛋白。在这项研究中，拟南芥（Arabidopsis thaliana）花粉与很少或没有MIKC* 活性的结合强烈的功能丧失等位基因的S类蛋白AGAMOUS-LIKE 66（AGL 66）和AGL 104。双突变体植物产生花粉，但由于花粉活力降低、发芽延迟和异常花粉管生长而具有严重降低的育性。突变体花粉的微阵列分析显示，MIKC* 调控的丧失对花粉基因表达有重大影响。涉及AGL 65、AGL 66、AGL 104和AGL 94突变体等位基因的各种组合的花粉竞争测定提供了遗传证据，证明在花粉中至少有三种异源二聚体（AGL 30-AGL 104、AGL 65-AGL 104和AGL 30-AGL 66）以至少部分冗余的方式形成和功能。野生型和突变花粉中转录本丰度的分析表明，含有AGL 65的复合物可能比其他复合物更丰富，并且AGL 30和AGL 94转录本的积累响应于MIKC* 活性的降低而增加。将这些结果组合以创建描述花粉中MIKC* 异二聚体贡献的模型。
MADS box genes encode transcription factors that play important regulatory roles at various stages in plant development. Transcripts encoding the MIKC*-type (for MADS DNA-binding domain, Intervening domain, Keratin-like domain, and C-terminal domain) factors, a divergent clade, are enriched in mature pollen. Previous studies have shown that these proteins bind DNA as heterodimers, which form between S-and P-class MIKC* proteins. In this study, Arabidopsis (Arabidopsis thaliana) pollen with little or no MIKC* activity was produced by combining strong loss-of-function alleles of the S-class proteins AGAMOUS-LIKE66 (AGL66) and AGL104. Double mutant plants produce pollen but have severely reduced fertility due to reduced pollen viability, delayed germination, and aberrant pollen tube growth. Microarray analysis of the mutant pollen revealed that the loss of MIKC* regulation has a major impact on pollen gene expression. Pollen competition assays involving various combinations of AGL65, AGL66, AGL104, and AGL94 mutant alleles provided genetic evidence that at least three heterodimers (AGL30-AGL104, AGL65-AGL104, and AGL30-AGL66) form and function in at least a partially redundant fashion in pollen. Analyses of transcript abundance in wild-type and mutant pollen indicated that AGL65-containing complexes are likely to be more abundant than the others and that accumulation of AGL30 and AGL94 transcripts increases in response to reductions in MIKC* activity. These results were combined to create a model to describe MIKC* heterodimer contributions in pollen.